Cal. Public Utilities Code § 463.5

(a) Section 463 does not require the commission to undertake a reasonableness review of recorded costs to determine the reasonableness of the costs of each item of any electrical or gas corporation’s plant which costs, or is estimated to have cost, more than fifty million dollars ($50,000,000) where the commission either has established a maximum reasonable cost pursuant to Section 1005.5 or has adopted an estimate of the reasonable costs in any proceeding. The establishment of the maximum costs or adoption of an estimated cost does not limit or restrict the discretion of the commission in considering the reasonableness of plant-related costs in subsequent proceedings. (b) This section shall become operative January 1, 1989.